[v3] iommu/vt-d: Fix a bug in intel_iommu_iova_to_phys() for huge page
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Message ID 20200226203006.51567-1-yonghyun@google.com
State Accepted
Commit 77a1bce84bba01f3f143d77127b72e872b573795
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Series
  • [v3] iommu/vt-d: Fix a bug in intel_iommu_iova_to_phys() for huge page
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Commit Message

Yonghyun Hwang Feb. 26, 2020, 8:30 p.m. UTC
intel_iommu_iova_to_phys() has a bug when it translates an IOVA for a huge
page onto its corresponding physical address. This commit fixes the bug by
accomodating the level of page entry for the IOVA and adds IOVA's lower
address to the physical address.

Cc: <stable@vger.kernel.org>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Yonghyun Hwang <yonghyun@google.com>
---

Changes from v2:
- a new condition is added to check whether the pte is present.

Changes from v1:
- level cannot be 0. So, the condition, "if (level > 1)", is removed, which results in a simple code.
- a macro, BIT_MASK, is used to have a bit mask

---
 drivers/iommu/intel-iommu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Joerg Roedel March 2, 2020, 4:08 p.m. UTC | #1
On Wed, Feb 26, 2020 at 12:30:06PM -0800, Yonghyun Hwang wrote:
> intel_iommu_iova_to_phys() has a bug when it translates an IOVA for a huge
> page onto its corresponding physical address. This commit fixes the bug by
> accomodating the level of page entry for the IOVA and adds IOVA's lower
> address to the physical address.
> 
> Cc: <stable@vger.kernel.org>
> Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Moritz Fischer <mdf@kernel.org>
> Signed-off-by: Yonghyun Hwang <yonghyun@google.com>

Applied with Fixes tag:

Fixes: 3871794642579 ("VT-d: Changes to support KVM")

Patch
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diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 932267f49f9a..0837e0063973 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5553,8 +5553,10 @@  static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
 	u64 phys = 0;
 
 	pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT, &level);
-	if (pte)
-		phys = dma_pte_addr(pte);
+	if (pte && dma_pte_present(pte))
+		phys = dma_pte_addr(pte) +
+			(iova & (BIT_MASK(level_to_offset_bits(level) +
+						VTD_PAGE_SHIFT) - 1));
 
 	return phys;
 }